1. Field of the Invention
This invention relates to a high frequency current inducing means, and more particularly to a high frequency current inducing means which induces high frequency current through a wiring harness to an instrument to be examined.
2. Description of the Prior Art
The electro-magnetic compatibility (EMC) of an electronic instrument with high frequency current has been widely studied and a high frequency current inducing means is conventionally required to induce the high frequency current to a wiring harness of an electronic instrument to be examined.
A high frequency current inducing means of the prior art includes a means that directly induces the high frequency current to the wiring harness by way of a capacitor. In the prior art means mentioned above, the examining operation becomes complicated especially if the wire is used in plurality since the wiring harness must be disconnected from the electronic instrument, and thus the high frequency current inducing means must be larger in size. Furthermore, there are other drawbacks in that the electric characteristics of the wires are affected since the capacitor must be in direct contact with the wires.
In the high frequency current inducing means of the other prior art devices a core type high frequency current probe is well known as well as a TEM cell of a large electro-magnetic shielded box in which the total body of the instrument to be examined is subjected to a high frequency electromagnetic field. The core type high frequency current inducing means in the prior art, however, is limited in its applicable frequency band by the high frequency characteristics of the core, and cannot perform efficient high frequency inducing action. Furthermore, as the TEM cell requires large scale facilities since the electronic instrument to be examined must be contained in the shielded box, the electronic instrument cannot be externally operated and cannot be simply examined by the high frequency current induction.